A small request can reopen an entire project when its decisions have disappeared into inboxes, documents and memory.
What was approved? Which constraint mattered? What failed? Without those answers, the newest message becomes the whole story.
The useful unit is not a pile of notes. It is a decision with its source, constraint, uncertainty and next use intact.
A Second Brain is not the brain. It is a retrieval interface for the context that makes future work less wasteful.